This invention relates to housing structures of ignition coil assemblies for internal combustion engines, which comprise, in addition to an ignition coil, an igniter circuit for controlling the primary current supplied to the ignition coil.
Conventional ignition systems for internal combustion engines of automotive vehicles generally comprise breaker points for interrupting the primary current in the ignition coil, in synchrony with the rotation of the engine. Recently, however, ignition systems have been developed which utilize semiconductor circuits (i.e., igniters) instead of the breaker points. FIG. 1 shows, in a circuit diagram, the portion of such an ignition system including the ignition coil 1 and the igniter 2, wherein the igniter 2 constitutes the control circuit for controlling the current supplied to the primary coil winding 1a of the ignition coil 1. In the case of conventional housing structures of these igniter or semiconductor type ignition systems for an engine of an automotive vehicle, the ignition coil 1 and the igniter 2 are accomodated in respective separate casings, wherein the casing accomodating the igniter 2 is mounted to the casing accomodating the ignition coil 1, or alternatively, the casing of the igniter 2 is accommodated within the distributor of the ignition system.
The above conventional housing structure of the ignition coil assembly of the igniter type ignition systems has the following disadvantage: The provision of separate casings for the ignition coil and the igniter increases the dimensions and production costs of the ignition coil assemblies.